New Threshold for Large Optic Discs in Children Using Bruch's Membrane Opening Area.

PURPOSE

To compare the peripapillary retinal nerve fiber layer (pRNFL) thickness of large optic discs in children (LOD-C) with normal sized optic discs in children (NOD-C) and large optic discs in adults (LOD-A).

METHODS

We included 127 eyes per group (n = 381). Optic discs were considered large if the Bruch's membrane opening (BMO) area was ≥2.5 mm2. pRNFL thickness and minimal rim width (BMO-MRW) were compared between the pediatric groups and the large optic disc groups.

RESULTS

The mean global pRNFL thickness (3.5-mm circle) was 100.2 ± 12.1 µm for LOD-C, 95.9 ± 11.7 µm for NOD-C, and 97.7 ± 10.5 µm for LOD-A. It was significantly thicker in LOD-C compared with NOD-C; the difference decreased toward the periphery. The mean global BMO-MRW was 280.0 ± 41.1 µm for LOD-C, 320.7 ± 10.5 µm for NOD-C, and 252.9 ± 45.8 µm for LOD-A. It was significantly thinner in LOD-C compared with NOD-C, and significantly thicker in LOD-C compared with LOD-A. pRNFL and BMO area showed a positive correlation which was higher if BMO area was >2.8 mm2, BMO-MRW and BMO are showed a negative correlation which was higher if BMO area was <1.9 mm2.

CONCLUSIONS

RNFL and BMO-MRW of pediatric optic discs with BMO area <1.9 mm2 and >2.8 mm2 should be interpreted with caution, because they seem to be strongly influenced by optic disc size.

TRANSLATIONAL RELEVANCE

The novel thresholds for small and LOD-C will help to account for the effects of disc status on RNFL and MRW. They will furthermore help clinicians to better diagnose children with suspicious discs for glaucoma.